Combination sub for drilling operations



Feb. 20, 1951 a. E. KEMNITZ 2,542,679

cousmnon $08 FOR DRILLING opm'rxous Filed March 18, 1950 IN VEN TOR.

-2 GEORGE E KEMNITZ 1 z-31 BY M i kyn 1;

ATTORNEYS Patented Feb. 20, 1951 UNITED STATES PATENT OFFICE-COMBINATION SUB FOR DRILLING v OPERATIONS George E. Kemnits, Tulsa,Okla., assignor to Noble Drilling Delaware Oorp., Tulsa, Okla.. acorporation oi Application March 18, 1950, Serial No. 150,531

- i This invention relates to well drilling tools and more particularlyto novel "sub" constructions for use in retrieving "fishes" duringdrillingon each. These connectors are commonly referred to as subs.Often in the drilling of wells, the drill pipe becomes stuck, because ofcaving in of the hole or the settling of sand or other sediments, and itis freed by use of what is called "wash-over pipe.

It is conventional practice to disconnect or back off the tool Jointjust above where the drill pipe is stuck, raise the disconnected partsout of the hole, apply a piece of wash-over pipe thereto, which may varyin length from a few feet to several hundred feet, go back into thehole, and wash over the stuck pipe by circulating drilling fluid throughthe'wash pipe and thus wash out the substance holding the stuck pipe.The wash-over pipe is, of course, of greater inside diameter than theoutside diameter of the drill pipe. After a considerable section of thestuck pipe has been washed over, the wash pipe is again pulled out ofthe hole and disconnected. The drill pipe part to which it has beenattached is then again lowered into the hole and connected with thewashed over section of drill pipe. Then back off shot or "string shot islowered into the thus connected drill pipe and stuck section.

This explosive string shot usually about 33 feet in length, a littlelonger than a length of drill pipe is lowered by electric wires insidethe drill pipe to the lowest tool joint washed over. Left hand torque isapplied to the drill pipe and the string shot is detonated. This has theeffect of jarring the joint loose so that it will readily unscrew, beingmuch the same as apply- 8 Claims. (01.294-86) of time is lost in thispractice in the round trip of the pipe sections above the stuck pipeneeded for disconnecting the wash pipe and then for going back into thewell with the drill pipe for application of the string shot and forretrieving the fish.

Principal objects and features of this invention are the provision of anovel "combination sub construction to which wash pipe may be connectedand which also has a connector that may be screwed into the freedsection of the pipe after it has been washed over, and permits loweringand detonation of string shot so that the washed-over section of pipemay be backed off and pulled out of the well without the necessity ofpreviously removing the wash pipe, thus eliminating one full round tripof the drill pipe for purposes of disconnecting the wash pipe, aspresently practiced, and going back in to retrieve the fish.

Further objects and features of the invention are the provision ofsimple effective combination sub" constructions, applicable for use withexisting drilling equipment, that are easy to use,

relatively low in cost and time saving in their use.

Other objects and novel featureswill become apparent from the followingspecification and accompanying drawings wherein similar referencecharacters denote corresponding parts and wherein:

. Fig. 1 is an elevational view of the device embodying the inventionshown in position of 1186;

Fig. 2 is a longitudinal section taken along line 2-2 of Fig. l andviewed in the direction of the arrows;

Fig. 3 is a transverse section taken along line 3-3 of Fig. 2;

Fig. 4 is a fragmentary longitudinal section similar to that of Fig. 3,showing parts in another position; and

Fig. 5 is a longitudinal section similar to that of Fig. 3 of a modifiedform of construction.

Referring to the drawing, l0 denotes a hole being drilled byconventional drilling equipment D including drill pipe H the lowermostlength Ha of which for purposes of this application is assumed to be thestuck pipe. The lengths of pipe II are strung together end to end beingconnected by conventional sub parts l2 and H41 in usual manner duringactual drilling operations, the uppermost pipe being suspended from thehead part l3 of the drilling equipment. The sub part I! in thisdisclosure is a female part 3 attached to the upper end of a drill pipelength while sub part In is a male part secured to the lower end of adrill pipe length.

The combination sub 8 embodying the invention, which is to be utilizedwhenever a drill pipe length becomes stuck comprises a tubular member I4whose upper end has a threaded socket IS, the threads of which areadapted to be screwed onto the right hand threads II on the pin and ofthe regular sub part or tool joint I2a on the lower end of the drillpipe above the stuck section Ila. The portion II of the tubular memberI4 below socket II is of substantially larger diameter than the drillpipe, and is threaded externally at I4 to receive threadedly a length ofwash pipe II. A portion 20 below the externally threaded portion I4 ofreduced diameter is also threaded externally at 20a for applicationthereto, if desirable, of wash pipe (not shown) of smaller diameter thanwash pipe I9.

The lower part of the tubular member I4 is further reduced in diameter,at portion 2I tapered and provided with an external preferably squareleft-hand thread 22, that is, thread running in opposite direction tothe threads I5.

Three segmental parts 22, 24, 25 internally tapered and threaded to fiton the left-hand thread 22 of portion 2| are threaded externally at 26with a tool joint right-hand thread for connection with the standardthreaded socket of the sub I2 carrying the stuck pipe section Ho. Theparts 23, 24 and 25 are held in place on the portion H by snap rings 21,28 fitting in the respective annular grooves 29, 30 in the parts 23, 24and 25. Below the left-hand threaded portion 2|, the body I4 extends asa nose or head it having a largest external diameter 32 dimensioned tofit slidably in the internal diameter of the bore in sub I2 and atapered leading part 33 to guide the head into the said bore.

In utilizing the combination sub assembly described when a drill pipelength IIa becomes stuck, the drill pipe above the stuck section isgiven clockwise rotation causing upper joint part In of the pipe lengthII just above the stuck section to be unscrewed from part I2 of thestuck section Ila. The detached pipe lengths including the justseparated part In are drawn upwardly out of the hole I0. The combinationsub S is then attached to the pin end It of the latter-named joint partHe by screwing the socket I of member I4 onto the said threaded pin endIS. Wash pipe I9 is then screwed onto threaded portion I8 of body I4 orthreaded part 20. The assembled parts are then lowered into the hole tothe level of the stuck pipe Ila and wash water or drilling fluid sentdown through the pipe lengths II and lower outlet end of the bore inbody I4 at its nose 3|. The wash water acts to wash away cave-in orblocking or clogging material about the stuck pipe Ila and permitgradual lowering of the nose II of body I4 into the bore of sub I2 ofthe stuck pipe until the threaded parts 23, 24 and 25 lie alined withthe threaded socket of this sub I2. The entire assembly is then rotatedcounterclockwise, or to the left. Friction between the threaded parts23, 24 and 25 and the socket of the said sub I2, causes the threadedleft-hand tapered portion 2I to screw into the socket defined by theinternal threads of parts 22, 24, 25 and expand these parts causingtheir external threads to fit in and engage the right-hand threads ofthe socket of the said sub I2. After the string shot has been loweredand as left-handed or counterclockwise rotation is continued, lefttorque is appliedto the drill pipe Ila through the tubular part so thatwhen the string shot" is detonated. the fish or pipe Ila is freed .andcan be pulled up out or the hole without unscrewing the members 22, 24,25 from sub I2.

Modification In the modified form of construction shown in Fig. 5, theessential diflerence is that only the externally threaded portion libcorresponding to threaded portion I8 is provided in the tubular partI4b. Likewise the nose SI of part I4 is replaced by a nose part III: onthe end of part I 4b which performs the function of nose II of tubularmember I4. Operation is substantially the same except that the device islimited to use of wash pipe of but a single diameter instead ofpermitting the use of differently diametered wash pipes in coniunctiontherewith.

While specific embodiments of the invention have been described andshown, variations in structural detail within the scope of the appendedclaims are possible and are contemplated. There is no intention,therefore, of limitation to the exact details shown and described.

7 What is claimed is:

l. A combination sub for use in hole drilling for the recovery of stucktool parts comprising a tubular member having a threaded socket at oneend for direct attachment to the conientional threads or a threaded pinend of a tool joint part, a portion having external threads forattachment thereto of a wash pipe, a tapered portion on said memberhaving an external thread in reverse direction to the thread directionof the threaded pin end, a plurality of tapered sectional partsinternally threaded to mate with the reversely directed external threadof said tapered portion mounted in assembled relationship on said last.

named thread, said tapered sectional parts bein tapered externally andprovided with external conventionally directed threads to match theconventional thread of an internally threaded socket of a second tooljoint part, said sectional parts being expansible to fit their externalthreads into threaded relationship with the internally threaded socketof said second tool joint part. upon rotation of said tapered portion ina direction to screw it into the internal threads of said sectionalparts.

2. The combination of claim 1 in which the tubular member has a nosepart for guiding the sectional parts into the internally threaded socketof said second tool joint part.

3. The combination of claim 1 in which snap rings mounted on saidsectional parts hold them expansibly in assembled relationship on saidtapered portion of said tubular member.

4. The combination of claim 1 in which said sectional parts have groovesand in which snap rings fitting within the grooves hold said sectionalparts expansibly in assembled relationship on said tapered portion ofsaid tubular member.

5. The combination of claim 1 in which said sectional parts have endportions shaped to define a guiding nose to facilitate guiding of theassembled sectional parts on said tapered portion into the internallythreaded socket of said second tool joint part.

6. The combination of claim 1 in which the external conventionallydirected threads are right hand threads and in which the external threadon said tapered portion i aleft handed thread.

a portion having external threads for attachment thereto of a wash pipe,a second portion of different diameter having external conventionallydirected threads for attachment thereto or a different diametered washpipe, a tapered portion on said member having an external thread inreverse direction to the thread direction of the threaded pin end, aplurality of tapered ectional parts internally threaded to mate with thereversely directed external thread of said tapered portion mounted inassembled relationship on said last named thread, said tapered sectionalparts being tapered externally and provided with external conventionallydirected threads to match the conventional thread of an internallythreaded socket of a second tool joint part, said sectional parts beingexpansible to fit their external threads into threaded relationship withthe internally threaded socket of said second tool joint part,

upon rotation of said tapered portion in a direction to screw it intothe internal threads of said sectional parts.

8. A combinationsub for use in hole drilling comprising a tubular memberhaving a threaded socket at one end for attachment to a threaded pin endof a tool joint part, a threaded external portion for attachmentthereto, of a wash pipe,

a tapered portion provided with a thread of reverse direction to that ofthe first named threaded portion, a plurality of internally threadedtapered parts mounted in assembled relationship on the reverse thread ofsaid tapered portion, expansible means for holding said parts on saidthreaded tapered portion, said internally threaded tapered parts beingexternally threaded to match No references cited.

